3D features of modified photostructurable glass-ceramic with infrared femtosecond laser pulses

The exclusive ability of laser radiation to be focused inside transparent materials makes lasers a unique tool to process inner parts of them unreachable with other techniques. Hence, laser direct-write can be used to create 3D structures inside bulk materials. Infrared femtosecond lasers are especially indicated for this purpose because a multiphoton process is usually required for absorption and high resolution can be attained. This work studies the modifications produced by 450 fs laser pulses at 1027 nm wavelength focused inside a photostructurable glass-ceramic (Foturan®) at different depths. Irradiated samples were submitted to standard thermal treatment and subsequent soaking in HF solution to form the buried microchannels and thus unveil the modified material. The voxel dimensions of modified material depend on the laser pulse energy and the depth at which the laser is focused. Spherical aberration and self-focusing phenomena are required to explain the observed results.

Research highlights▶ Microchannels buried at different depths in Foturan were fabricated with femtosecond laser pulses at 1027 nm wavelength. ▶ The microchannel size along the laser beam direction can be controlled through adjustment of the pulse energy for the different depths. ▶ The voxel size in the laser beam direction follows a logarithmic relationship with pulse energy, and an exponential relationship with focusing depth. ▶ Spherical aberration and self-focusing phenomena account for the laser intensity distribution inside Foturan.